Answer:
\sqrt{81 + x^2} = y
\sqrt{y^2 - 7^2} = x
Step-by-step explanation:
They would be Pythagorean Triples.
a^2 + b^2 = c^2
9^2 + x^2 = y^2
7^2 + x^2 = y^2
x^2 = y^2 - 7^2
